title: Insertional gene activation by lentiviral and gammaretroviral vectors.
abstract: Gammaretroviral and lentiviral vectors are promising tools for gene therapy, but they can be oncogenic. The development of safer vectors depends on a quantitative assay for insertional mutagenesis. Here we report a rapid, inexpensive, and reproducible assay which uses a murine cell line to measure the frequency of interleukin-3 (IL-3)-independent mutants. Lentiviral and gammaretroviral vectors cause insertional mutagenesis at similar frequencies; however, they use different mechanisms. Human immunodeficiency virus (HIV)-based vectors generate mutants by insertion only into the growth hormone receptor (Ghr) locus. The HIV enhancer/promoter is active in the absence of the HIV Tat protein in this locus, and an HIV/Ghr spliced transcript expresses GHR and cells respond to GH. Deletion of the enhancer/promoter in a self-inactivating HIV-based vector prevents this mechanism of insertional mutagenesis. In contrast, gammaretroviral vectors insert into other loci, including IL-3 and genes identified as common insertion sites in the Retroviral Tagged Cancer Gene Database (RTCGD).
authors.affiliation: Infection and Immunity, University College London, Windeyer Building, 46 Cleveland Street, London W1T 2AH, United Kingdom.
authors.forename: Marieke
authors.initials: M
authors.lastname: Bokhoven
authors.forename: Sam L
authors.initials: SL
authors.lastname: Stephen
authors.forename: Sean
authors.initials: S
authors.lastname: Knight
authors.forename: Evelien F
authors.initials: EF
authors.lastname: Gevers
authors.forename: Iain C
authors.initials: IC
authors.lastname: Robinson
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Mary K
authors.initials: MK
authors.lastname: Collins
mesh_terms: D000818:Animals; D002460:Cell Line; D017988:Gammaretrovirus / Q000235:genetics*; D015316:Genetic Therapy / Q000009:adverse effects*; D005822:Genetic Vectors / Q000009:adverse effects*; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D016254:Mutagenesis, Insertional